DR Check - Dynamic Range Analyzer

DR Check is a modern, fast, and accurate tool for measuring the dynamic range (DR) of audio files using the DR14 algorithm. Built from the ground up in Python, it provides professional-grade analysis with beautiful output formats.

Fight the Loudness War by analyzing and comparing the dynamic range of your music collection!

✨ Features

• 🎯 Accurate DR14 Calculation - Validated against professional tools (foobar2000 DR Meter)
• 📁 Multiple Audio Formats - FLAC, WAV, MP3, M4A, OGG, AIFF, and more
• 🎨 Beautiful HTML Reports - Modern, responsive design with automatic album art extraction
• 📊 Multiple Output Formats - Text tables, BBCode (for forums), CSV, and HTML
• 🔍 Batch Processing - Analyze entire albums or recursively scan music libraries
• ⚡ Parallel Processing - Multi-core support for high-speed library analysis
• 🎵 Metadata Support - Extracts artist, album, sample rate, bit depth, and format info
• 💡 Smart Error Messages - Helpful, actionable error messages with install instructions
• 🖼️ Optimized Album Art - Automatic image resizing for smaller HTML reports (with Pillow)
• 🧪 Well Tested - Comprehensive test suite with 81+ passing tests

📸 Screenshots

Text Output

DR Check - Dynamic Range Analyzer v1.1.0
log date: 2026-01-10 10:40:05

--------------------------------------------------------------------------------
Analyzed: Willie Nelson / Red Headed Stranger
--------------------------------------------------------------------------------

DR     Peak           RMS            Duration  Track
--------------------------------------------------------------------------------
DR11   -1.28 dBFS     -16.66 dBFS    2:25      01. Time Of The Preacher
DR11   -1.60 dBFS     -17.18 dBFS    1:32      02. I Couldn't Believe It Was True
DR11   -0.16 dBFS     -16.93 dBFS    1:13      03. Time Of The Preacher Theme
DR14   -3.38 dBFS     -20.01 dBFS    1:35      04. Medley- Blue Rock Montana - Red Headed Stranger
DR11   -2.00 dBFS     -16.81 dBFS    2:21      05. Blue Eyes Crying In The Rain
DR12   -1.10 dBFS     -16.32 dBFS    3:59      06. Red Headed Stranger
DR12   -4.35 dBFS     -19.44 dBFS    0:26      07. Time Of The Preacher Theme
DR11   -1.91 dBFS     -19.03 dBFS    1:48      08. Just As I Am
DR12   -2.55 dBFS     -18.47 dBFS    0:53      09. Denver
DR12   -6.14 dBFS     -21.08 dBFS    0:47      10. O'er The Waves
DR11   -3.83 dBFS     -17.57 dBFS    1:56      11. Down Yonder
DR12   -2.12 dBFS     -18.11 dBFS    5:23      12. Can I Sleep In Your Arms
DR11   -1.60 dBFS     -15.38 dBFS    2:52      13. Remember Me (When The Candle Lights Are Gleaming)
DR12   -0.65 dBFS     -15.98 dBFS    4:22      14. Hands On The Wheel
DR11   -3.52 dBFS     -18.10 dBFS    2:15      15. Bandera
--------------------------------------------------------------------------------

Number of tracks:  15
Official DR value: DR12

Samplerate:        96000 Hz
Channels:          2
Bits per sample:   24
Bitrate:           4608 kbps
Codec:             FLAC
================================================================================

HTML Output

Beautiful, modern reports with:

• Album artwork (automatically extracted)
• Color-coded DR values (green/orange/red)
• Responsive design for desktop and mobile
• Optimized images for faster loading
• Professional styling

🚀 Quick Start

Installation

PyPi

# pip
pip install drcheck

# pipx
pipx install drcheck

Local git checkout w/ uv

# Clone the repository
git clone https://github.com/nixternal/drcheck.git
cd drcheck

# Install with uv (recommended)
uv pip install -e .

# Or with pip
pip install -e .

Basic Usage

# Analyze a single file
drcheck analyze song.flac

# Analyze an entire album
drcheck analyze /path/to/album/

# Recursive scan of music library
drcheck analyze -r /path/to/music/library/

# Save results to file
drcheck analyze album/ --save

# Generate HTML report
drcheck analyze album/ --save --format html

📖 Usage Guide

Commands

analyze

Analyze audio files and calculate DR14 values.

drcheck analyze [OPTIONS] PATHS...

Options:

• -r, --recursive - Recursively scan subdirectories
• --show-channels - Show per-channel DR values for stereo files
• --save - Save results to file
• -o, --output DIR - Output directory (default: source directory)
• --format FORMAT - Output format: text, bbcode, csv, html (default: text)
• --filename NAME - Output filename (default: dr.txt, auto-adjusts extension)
• -j, --workers N - Number of parallel workers (auto-selects based on job size)

Examples:

# Single file analysis
drcheck analyze mysong.flac

# Album analysis with text output
drcheck analyze album_folder/

# Save as HTML report
drcheck analyze album/ --save --format html

# Recursive scan, save as CSV
drcheck analyze -r music_library/ --save --format csv -o ~/reports/

# Show per-channel DR values
drcheck analyze stereo_file.flac --show-channels

# Multiple paths
drcheck analyze album1/ album2/ single.flac

# Parallel processing with 4 workers
drcheck analyze -r music_library/ -j 4

scan

Preview files that would be analyzed without processing them.

drcheck scan [OPTIONS] PATH

Options:

• -r, --recursive - Recursively scan subdirectories

Example:

drcheck scan -r /music/library/

version

Show detailed version information including Python version, platform, and supported formats.

formats

List all supported audio formats.

drcheck formats

Output Formats

Text (default)

Clean ASCII tables suitable for terminals and text files.

drcheck analyze album/ --save --format text

HTML

Beautiful, modern reports with album art and color-coded DR values.

drcheck analyze album/ --save --format html

Features:

• Automatic album art extraction (from files or folder images)
• Responsive design (mobile-friendly)
• Color-coded DR values
• Complete technical information
• Self-contained (single HTML file)

Example of size reduction:

Before (without Pillow):
  Album art: 2.4 MB → HTML report: 3.2 MB

After (with Pillow):
  Album art: 2.4 MB → 85 KB → HTML report: 320 KB

Savings: 90% smaller files!

BBCode

Formatted for posting on audio forums.

drcheck analyze album/ --save --format bbcode

CSV

Spreadsheet-compatible format for data analysis.

drcheck analyze album/ --save --format csv

Or pipe directly:

drcheck analyze album/ --format csv > results.csv

🎵 Supported Audio Formats

Lossless (via libsndfile):

• FLAC (.flac)
• WAV (.wav)
• AIFF (.aiff, .aif, .aifc)
• OGG Vorbis (.ogg, .oga)
• Opus (.opus)

Lossy (requires pydub + ffmpeg):

• MP3 (.mp3)
• M4A/AAC (.m4a, .mp4, .aac)
• WMA (.wma)

To enable MP3/M4A support:

# Install pydub
uv pip install pydub

# Install ffmpeg (system package)
# Ubuntu/Debian:
sudo apt install ffmpeg

# macOS:
brew install ffmpeg

# Arch Linux:
sudo pacman -S ffmpeg

🔬 Understanding DR Values

The DR (Dynamic Range) scale measures the difference between the loudest and average loudness of an audio track:

DR Value	Quality	Description
DR14+	🟢 Excellent	Wide dynamic range, natural sound
DR8-13	🟡 Good	Moderate compression, still enjoyable
DR0-7	🔴 Poor	Heavily compressed, "loudness war" victim

Note: Higher DR doesn't always mean "better" - it depends on the genre and artistic intent. Classical and jazz typically have DR14+, while modern pop/rock often ranges from DR6-10.

📊 Error Handling (v1.1.1)

Smart Error Messages (v1.1.1): When errors occur, DR Check now provides helpful, actionable guidance:

• Missing MP3/M4A support? Shows exact install command
• Corrupted files? Suggests how to fix them
• Audio too short? Explains the 6-second minimum requirement

Examples of intelligent error messages with helpful suggestions:

================================================================================
⚠️  Failed to process 3 of 50 file(s)
================================================================================

📋 Missing Lossy Format Support (2 file(s)):
   • song1.mp3
     → Install: pip install drcheck[lossy]
     → Also ensure ffmpeg is installed on your system

📋 Audio Too Short (1 file(s)):
   • intro.wav (need at least 6 seconds for DR analysis)

💡 Tips:
   • For MP3/M4A support, install: pip install drcheck[lossy]
   • DR analysis requires at least 6 seconds of audio
     (two 3-second blocks for measurement)

🧪 Development

Running Tests

# Install dev dependencies
uv pip install pytest pytest-cov

# Run all tests
pytest tests/ -v

# Run with coverage report
pytest tests/ --cov=drcheck --cov-report=html

# Run specific test file
pytest tests/test_analysis.py -v

Project Structure

drcheck/
├── drcheck/              # Main package
│   ├── __init__.py
│   ├── analysis.py       # Core DR14 calculation
│   ├── audio.py          # Audio file reading
│   ├── cli.py            # Command-line interface
│   ├── formatters.py     # Output formatting
│   └── parallel.py       # Parallel processing
├── tests/                # Test suite
│   ├── test_analysis.py
│   ├── test_audio.py
│   ├── test_formatters.py
│   └── test_parallel.py
├── README.md
└── pyproject.toml

Code Quality

• ✅ Full type hints (pyright compliant)
• ✅ Modern Python 3.10+ features
• ✅ Comprehensive test coverage (81+ tests)
• ✅ Clean, documented code
• ✅ Follows Python best practices

🤝 Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Guidelines

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Make your changes
4. Add tests for new functionality
5. Ensure all tests pass (pytest tests/)
6. Commit your changes (git commit -m 'Add amazing feature')
7. Push to the branch (git push origin feature/amazing-feature)
8. Open a Pull Request

📝 License

This project is licensed under the GNU General Public License v3.0 - see the LICENSE file for details.

🙏 Acknowledgments

• Based on the DR14 algorithm by the Pleasurize Music Foundation
• Inspired by the original dr14_t.meter by Simone Riva
• Validated against the foobar2000 DR Meter plugin

🔗 Related Resources

• Dynamic Range Database - Browse DR values for albums
• Pleasurize Music Foundation - Learn about the DR measurement
• Loudness War - Wikipedia article on the loudness war

📧 Contact

• Issues: GitHub Issues
• Discussions: GitHub Discussions

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Made with ❤️ for music lovers who care about sound quality